PHP Chat Application Backend Transition to Mongo DB

Requiring a skilled developer to transition my existing CORE PHP chat application from MYSQL to MONGO DB using NODE JS server. Essentials to the project include integration into our existing PHP application, with key features of real-time messaging, user authentication, message history retrieval, file upload capabilities, notifications, and group chats and other features of chat applications we see in the market.

Ideal Skills:
* MongoDB
* Node.js
* PHP
* Real-Time Communication

The candidate should possess a strong understanding of chat applications and server handling to perform this transition smoothly.

My budget is $400